Separator for fuel cell

ABSTRACT

A fuel cell separator is provided which has in a peripheral part ( 30 ) gas passages ( 31, 31 ) for guiding reaction gases and reaction product passages ( 33 ) for guiding a reaction product. The separator ( 20 ) is made up of a central part ( 22 ) made of metal, a peripheral part ( 30 ) made of a resin material, and an elastic member ( 40 ) connecting the central part and the peripheral part together. As a result of the peripheral part being made of a resin material, the gas passages and product passages are resistant to corrosion.

TECHNICAL FIELD

This invention relates to a fuel cell separator having multiple passagesprovided in a peripheral part of the separator and used to guidereaction gases and a reaction product.

BACKGROUND ART

FIG. 10 shows a fuel cell of related art. This fuel cell 100 is made bydisposing a negative electrode 102 and a positive electrode 103respectively on the upper face side and the lower face side of anelectrolyte membrane 101, placing a separator 105 on the upper side ofthe negative electrode 102 and sandwiching the peripheral vicinity ofthe electrolyte membrane 101 and the peripheral vicinity of the upperside separator 105 with an upper side gasket 106, and placing aseparator 105 on the lower side of the positive electrode 103 andsandwiching the peripheral vicinity of the electrolyte membrane 101 andthe peripheral vicinity of the lower side separator 105 with a lowerside gasket 106.

With this fuel cell 100, hydrogen gas is supplied through multiplehydrogen gas passages 107 as shown by the arrow a. The hydrogen gas inthe hydrogen gas passages 107 is guided toward a central part 105 a ofthe upper side separator 105 as shown with an arrow. Oxygen gas issupplied through multiple oxygen gas passages 108 as shown by the arrowb. The oxygen gas in the oxygen gas passages 108 is guided toward thecentral part 105 a of the lower side separator 105 as shown with anarrow.

As a result of hydrogen gas being introduced into the upper side centralpart 105 a, hydrogen molecules (H₂) come into contact with a catalystincluded in the negative electrode 102, and as a result of oxygen gasbeing introduced into the lower side central part 105 a, oxygenmolecules (O₂) come into contact with a catalyst included in thepositive electrode 103, and electrons e⁻ flow as shown with an arrow anda current is produced.

At this time, product water (H₂O) is produced from the hydrogenmolecules (H₂) and the oxygen molecules (O₂), and this product waterflows through multiple product water passages 109 as shown by the arrowc.

In this fuel cell 100, to maintain resistance to corrosion of the gaspassages 107, 108 and the product water passages 109, it is necessaryfor the gas passages 107, 108 and the product water passages 109 to besealed. To achieve this, in the manufacture of the fuel cell 100, theupper side gasket 106 is sandwiched in the gap between the peripheralvicinity of the electrolyte membrane 101 and the peripheral vicinity ofthe upper side separator 105, and the lower side gasket 106 issandwiched in the gap between the peripheral vicinity of the electrolytemembrane 101 and the peripheral vicinity of the lower side separator105.

Here, it is desirable for the fuel cell 100 to be compact, and it isnecessary for the upper and lower gaskets 106 to be made thin.Consequently, handling of the upper and lower gaskets 106 has beendifficult, it has taken time for the upper and lower gaskets 106 to bedisposed in the proper positions, and this has constituted a hindranceto raising fuel cell productivity.

As a method of resolving this problem, for example the ‘ManufacturingMethod of a Silicone Resin—Metal Composite Body’ of JP-A-11-309746 hasbeen proposed. According to this method, gaskets can be eliminated byforming a silicone resin (hereinafter, ‘seal’) around the peripheralpart of the separator. An injection-molding mold for manufacturing afuel cell separator of related art is shown in FIG. 11, and a separatormanufacturing method of related art will now be described.

Referring to FIG. 11, by an injection-molding mold 110 being closed, aseparator 113 is inserted in a gap between a fixed die 111 and a movingdie 112 and a cavity 114 is formed by the fixed die 111 and the movingdie 112, and by the cavity 114 being filled with molten resin as shownwith an arrow, a seal 115 is formed on a peripheral part 113 a of theseparator 113.

By the seal 115 being formed around the peripheral part 113 a of theseparator 113 like this, the upper and lower gaskets 106 shown in FIG.10 can be made unnecessary. Therefore, in the manufacture of the fuelcell, it is possible to dispense with a step of incorporating the upperand lower gaskets 106.

To prevent the gas passages and product water passages of the separator113 from being corroded by the gases and product water, it is necessaryfor the entire surfaces of the gas passages and the product waterpassages to be covered. Because of this, it is necessary not only forthe upper face and the lower face of the peripheral part 113 a of theseparator 113 to be covered by the seal 115, but also for the wall facesof the gas passages and product water passages in the peripheral part113 a to be covered by the seal 115.

To cover the entire surfaces of the gas passages and product waterpassages of the peripheral part 113 a with the seal 115 to raise theirresistance to corrosion like this, it is necessary to raise theprecision of equipment such as the injection-molding mold 110, equipmentcosts consequently rise, and this constitutes a hindrance to keepingcosts down.

And even if the precision of the equipment is raised, it is difficult tocover the entire surfaces of the gas passages and product water passagesof the peripheral part 113 a with the seal 115, and yield in themanufacture of the separators is likely to fall, and this hasconstituted a hindrance to raising fuel cell productivity. Thus, a fuelcell separator has been awaited with which it is possible to securecorrosion resistance of the separator and also raise productivity aswell as keeping costs down.

DISCLOSURE OF THE INVENTION

The invention provides, in a fuel cell separator having provided in aperipheral part gas passages for guiding reaction gases and reactionproduct passages for guiding a reaction product, reaction gases beingguided from the gas passages to a central part and reaction productproduced at the central part being guided to the reaction productpassage, a fuel cell separator characterized in that the central part ismade a metal member and the peripheral part is made a resin member andthis resin member is connected to the metal member by an elastic member.

By making the entire peripheral part of the separator a resin member andforming gas passages and product water passages in this peripheral partlike this, it is possible to secure resistance of the gas passages andproduct water passages to corrosion by the gases and product water.

And, a construction is adopted wherein the peripheral part of theseparator is made a resin member and the peripheral part is connected tothe central part by an elastic member. As a result of this, it is notnecessary for the wall faces of the gas passages and the product waterpassages of the separator to be covered with a sealing material as inrelated art, and the peripheral part and the elastic member can bemolded with a mold of ordinary precision. Consequently, because it isnot necessary to use a high-precision mold, costs of equipment such asmolds can be kept down.

Also, by the peripheral part of the separator being connected to thecentral part by an elastic member, the separator can be manufacturedrelatively easily. Therefore, the yield in the production of separatorscan be raised.

Here, because the resin member has a different thermal expansioncoefficient from the metal member, if the resin member constituting theperipheral part were to be connected to the metal member constitutingthe central part directly, there would be a risk of the central partdeforming or the peripheral part suffering fatigue failure due todifferential thermal expansion between the peripheral part and thecentral part. To avoid this, in this invention, the peripheral part isconnected to the central part by way of an elastic member. As a result,because differential thermal expansion between the peripheral part andthe central part can be absorbed by the elastic member, deformation ofthe central part and fatigue failure of the peripheral part due todifferential thermal expansion between the two can be prevented.

Also, in this invention, preferably, a projecting central seal partsurrounding the central part is provided on the elastic member. That is,when a projecting central seal part surrounding the central part isprovided on the elastic member, in the assembling of the separator, itis not necessary to incorporate a central part gasket for surroundingthe central part. Consequently, in the assembling of a fuel cell, it ispossible to dispense with the trouble of incorporating a central partgasket.

In addition, in the assembling of the separator to a fuel cell, thecentral part can be surely sealed by the projecting central seal part.As a result, gases guided to the central part can be surely guided tothe proper position, and reaction product produced in the central partcan be surely guided to the proper position.

Also, in this invention, preferably, projecting passage seal partsseverally surrounding the gas passages and the reaction product passagesare provided on the peripheral part. When projecting passage seal partsseverally surrounding the gas passages and the reaction product passagesare provided on the peripheral part like this, in the assembling of theseparator, it is not necessary to incorporate passage gaskets forsurrounding the gas passages and the reaction product passages. As aresult, in the assembling of a fuel cell, it is possible to eliminatethe trouble of incorporating passage gaskets. Furthermore, in theassembling of the separator, the gas passages and reaction productpassages can be surely sealed with the projecting passage seal parts.

Also, in the invention, preferably, the elastic member and the centralseal part are formed integrally from a rubber material. When the elasticmember and the central seal part are formed integrally from a rubbermaterial like this, these members can be formed simultaneously.Consequently, the elastic member and the central seal part can be formedeasily in a short time.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded perspective view of a fuel cell having a fuel cellseparator according to the invention;

FIG. 2 is a sectional view on the line 2-2 in FIG. 1;

FIG. 3A is a sectional view on the line 3A-3A in FIG. 2, and FIG. 3B isa sectional view on the line 3B-3B in FIG. 2;

FIG. 4A and FIG. 4B are first action views illustrating steps in themanufacture of a fuel cell separator according to the invention, FIG. 4Ashowing a primer treatment having been carried out on the edge of acentral part of a separator and FIG. 4B showing a primer-treatedseparator being placed on a fixed die mounted on a turntable;

FIG. 5A and FIG. 5B are second action views illustrating steps in themanufacture of a fuel cell separator according to the invention, FIG. 5Ashowing a separator placed on a fixed die of a peripheral part mold andFIG. 5B showing a movable die lowered to close the peripheral part mold;

FIG. 6A and FIG. 6B are third action views illustrating steps in themanufacture of a fuel cell separator according to the invention, FIG. 6Abeing an enlarged sectional view of a part 6A in FIG. 5B and FIG. 6Bbeing a sectional view showing a molded peripheral part of a separator;

FIG. 7A and FIG. 7B are fourth action views illustrating steps in themanufacture of a fuel cell separator according to the invention, FIG. 7Abeing a view showing a turntable and an elastic member injection-moldingapparatus for molding an elastic member of a separator and FIG. 7B beinga sectional view of an elastic member mold as a second moving die islowered onto a fixed die with a separator placed upon it;

FIG. 8A and FIG. 8B are fifth action views illustrating steps in themanufacture of a fuel cell separator according to the invention, FIG. 8Abeing a sectional view of the elastic member mold closed and FIG. 8Bbeing an enlarged sectional view of a part 8B in FIG. 8A;

FIG. 9A and FIG. 9B are sixth action views illustrating steps in themanufacture of a fuel cell separator according to the invention, FIG. 9Abeing a sectional view showing an elastic member having been molded andthe mold about to open and FIG. 9B being a view showing the manufactureof a separator according to the invention having been completed and theseparator being removed from the fixed die;

FIG. 10 is an exploded perspective view of a fuel cell of related art;and

FIG. 11 is a sectional view showing a manufacturing method of a fuelcell separator of related art wherein a seal is molded to a peripheralpart of a separator in an injection-molding mold.

BEST MODES FOR CARRYING OUT THE INVENTION

A fuel cell 10 according to the invention shown in FIG. 1 has astructure wherein a negative electrode 15 and a positive electrode 16are respectively disposed on the upper face 11 a side and the lower face11 b (see FIG. 2) side of an electrolyte membrane 11 and an upper sideseparator 20 (fuel cell separator) is superposed on the negativeelectrode 15 and a lower side separator 20 is superposed on the positiveelectrode 16.

Here, generally the fuel cell 10 made by stacking the electrolytemembrane 11, the negative electrode 15, the positive electrode 16 andthe upper and lower separators 20, 20 is referred to as a cell, andmultiple cells arrayed in a stack are referred to as a fuel cell;however, in this specification, to facilitate understanding, the cellwill be called a fuel cell.

In a peripheral part thereof, the electrolyte membrane 11 has multiplehydrogen gas passages (gas passages) 12 for guiding hydrogen gas (areaction gas), multiple oxygen gas passages (gas passages) 13 forguiding oxygen gas (a reaction gas), and multiple product water passages(reaction product passages) 14 for guiding product water (a reactionproduct).

The negative electrode 15 and the positive electrode 16 are each formedsomewhat smaller than the electrolyte membrane 11. The peripheries ofthe negative electrode 15 and the positive electrode 16 are positionedinward of the hydrogen gas passages 12, the oxygen gas passages 13 andthe product water passages 14.

The separators 20 each have a metal central part 22, a resin peripheralpart 30 around that, and an elastic member 40 connecting the centralpart 22 and the peripheral part 30 together.

The peripheral part 30 has multiple hydrogen gas passages (gas passages)31 for guiding hydrogen gas, multiple oxygen gas passages (gas passages)32 for guiding oxygen gas, and multiple product water passages (reactionproduct passages) 33 for guiding product water.

By the peripheral part 30 of each of the separators 20 being made aresin member and this peripheral part 30 being provided with hydrogengas passages 31, oxygen gas passages 32 and product water passages 33,corrosion resistance of the hydrogen gas passages 31, the oxygen gaspassages 32 and the product water passages 33 with respect to the gasesand product water is ensured.

The multiple hydrogen gas passages 31 and oxygen gas passages 32 formedin the peripheral part 30 of each separator 20 are formed in locationssuch that they are aligned with the multiple hydrogen gas passages 12and oxygen gas passages 13 formed in the peripheral parts of theelectrolyte membrane 11 when the fuel cell 10 is assembled.

Also, the multiple product water passages 33 formed in each separator 20are formed in locations such that they are aligned with the multipleproduct water passages 14 formed in the electrolyte membrane 11 when thefuel cell 10 is assembled.

With this fuel cell 10, hydrogen gas is supplied through the hydrogengas passages 31, 12 as shown by the arrow A and guided to between thenegative electrode 15 and the central part of the upper side separator20 as shown by the arrow B. Oxygen gas is supplied through the oxygengas passages 32, 13 as shown by the arrow C and guided to between thepositive electrode 16 and the central part 22 of the lower sideseparator 20 as shown by the arrow D.

As a result of hydrogen gas being guided to the central part 22,hydrogen molecules (H₂) are brought into contact with a catalystincluded in the negative electrode 15, and as a result of oxygen gasbeing guided to the central part 22, oxygen molecules (O₂) are broughtinto contact with a catalyst included in the positive electrode 16, andelectrons e⁻ flow as shown with an arrow and a current is produced.

At this time, product water (H₂O) is produced from the hydrogenmolecules (H₂) and the oxygen molecules (O₂). This product water isguided to the product water passages 14, 33 as shown by the arrow E fromthe central part 22, and flows as shown by the arrow F.

FIG. 2 shows the fuel cell separators 20 each made up of a metal centralpart 22, a resin peripheral part 30 and an elastic member 40.

The central part 22 is a metal member and is a stainless steel platehaving multiple flow passages 23 for guiding hydrogen gas and multipleflow passages 24 for guiding oxygen gas formed in its upper face 22 aand its lower face 22 b, and passages for guiding product water (notshown), and having had an anti-corrosion plating treatment carried outon its upper face 22 a and lower face 22 b.

This central part 22 has primer-treated parts 25 a, 25 b, on which aprimer treatment has been carried out, on its upper and lower facesaround its edge part 22 c, and has multiple first openings 26 providedat a predetermined spacing in the primer-treated parts 25 a, 25 b.

The shape of the first openings 26 may be round holes, slots orrectangular, and there is no restriction on this. The reasons forproviding the primer-treated parts 25 a, 25 b and the first openings 26will be discussed later.

The peripheral part 30 is a frame formed somewhat larger than thecentral part 22, and is a frame made of an engineering plastic with themultiple hydrogen gas passages 31, oxygen gas passages 32 and productwater passages 33 (the passages 32, 33 are shown in FIG. 1) formed inthis frame.

On the upper face 30 a of the peripheral part 30, multiple projectingpassage seal parts 34 are provided along the respective edges of thehydrogen gas passages 31, the oxygen gas passages 32 and the productwater passages 33 so as to individually surround the hydrogen gaspassages 31, oxygen gas passages 32 and product water passages 33.

Also, on the lower face 30 b of the peripheral part 30, multiple passagerecesses 35 are provided along the respective edges of the hydrogen gaspassages 31, the oxygen gas passages 32 and the product water passages33 so as to individually surround the hydrogen gas passages 31, oxygengas passages 32 and product water passages 33.

In addition, in this peripheral part 30, by upper and lower recesses 36a, 36 b being formed in the upper face 30 a and the lower face 30 balong the inner edge 30 c, a part running along the inner edge 30 c ismade a thin part 37, and multiple second openings 38 are provided at apredetermined spacing in this thin part 37.

The shape of the second openings 38 may be round holes, slots orrectangular, and there is no restriction on this. The reason forproviding the second openings 38 will be discussed later.

By the frame of the peripheral part 30 being formed somewhat larger thanthe central part 22, a gap S can be provided between the inner edge 30 cof the peripheral part 30 and the edge 22 c of the central part 22.

The projecting passage seal parts 34 are formed so that when the fuelcell 10 is assembled, they are pressed against the passage recesses 35of the separator 20 disposed above on the other side of the passages 12,13 and 14 (see FIG. 1 for passages 13, 14) of the electrolyte membrane11.

Because at its peripheral part the projecting passage seal parts 34 areprovided so as to surround the hydrogen gas passages 31, the oxygen gaspassages 32 and the product water passages 33 individually, in theassembly of the separator 20 to the fuel cell 10 it is not necessary toincorporate a passage gasket for surrounding the hydrogen gas passages31, oxygen gas passages 32 and product water passages 33. Consequently,in assembling the fuel cell 10, it is possible to dispense with thetrouble of incorporating passage gaskets.

In addition, because the projecting passage seal parts 34 are providedso as to surround the hydrogen gas passages 31, the oxygen gas passages32 and the product water passages 33 individually, in the assembling ofthe separator 20 to the fuel cell 10, the projecting passage seal parts34 can be pressed against the passage recesses 35 to surely seal thehydrogen gas passages 31, oxygen gas passages 32 and product waterpassages 33.

The elastic member 40 is a connecting member made of silicone rubberwhich covers the primer-treated parts 25 a, 25 b of the central part 22and the thin part 37 of the peripheral part 30, fills the first openings26 and the second openings 38, and has on its upper face 40 a aprojecting central seal part 41 (see also FIG. 1) surrounding thecentral part 22.

Because the elastic member 40 is provided with a projecting central sealpart 41 surrounding the central part 22, when the fuel cell 10 isassembled, it is not necessary to incorporate a central gasket forsurrounding the central part 22. As a result, in the assembling of thefuel cell 20, it is possible to dispense with the trouble ofincorporating a central gasket.

In addition, in the assembling of the separator 20, the projectingcentral seal part 41 can be pushed against the electrolyte membrane 11to surely seal the central part 22. By this means, the hydrogen gas andoxygen gas guided to the central part 22 can be surely guided to theproper positions, and product water produced in the central part 22 canbe surely guided to the proper position.

Also, because the elastic member 40 and the central seal part 41 areformed integrally from silicone rubber (rubber material), the elasticmember 40 and the central seal part 41 can be formed simultaneously.Consequently, the elastic member 40 and the central seal part 41 can beformed easily in a short time.

Here, in the separator 20, when the upper and lower primer-treated parts25 a, 25 b of the central part 22 are covered with the elastic member 40and the thin part 37 of the peripheral part 30 is covered with theelastic member 40, by the first openings 26 and the second openings 38each being filled with the elastic member 40, first anchors 42 can beprovided in the first openings 26 and second anchors 43 can be providedin the second openings 38.

By this means, it is possible to prevent the central part 22 fromdetaching from the elastic member 40 and to prevent the peripheral part30 from detaching from thee elastic member 40 and thereby to firmlyconnect the peripheral part 30 to the central part 22.

Because the engineering plastic of the peripheral part 30 has adifferent thermal expansion coefficient from the stainless steel of thecentral part 22, if the peripheral part 30 were to be connected to thecentral part 22 directly, it is likely that the central part 22 woulddeform or the peripheral part 30 would suffer fatigue failure due todifferential thermal expansion between the peripheral part 30 and thecentral part 22.

To avoid this, by the peripheral part 30 being connected to the centralpart 22 by way of the elastic member 40, differential thermal expansionbetween the peripheral part 30 and the central part 22 is absorbed. Bythis means, deformation of the central part 22 and fatigue failure ofthe peripheral part 30 due to differential thermal expansion between theperipheral part 30 and the central part 22 can be prevented.

The projecting central seal part 41 is formed so as to be pressedagainst the electrolyte membrane 11 when the fuel cell 10 is assembled.

FIG. 3A and FIG. 3B are a sectional view on the line 3A-3A and asectional view on the line 3B-3B in FIG. 2.

FIG. 3A shows the first openings 26 formed as slots, as an example, andfirst anchors 42 provided in the first openings 26 by these slots beingfilled with the elastic member 40.

FIG. 3B shows the second openings 38 formed as slots, as an example, andsecond anchors 43 provided in the second openings 38 by these slotsbeing filled with the elastic member 40.

Next, a process for manufacturing the fuel cell separator 10 will bedescribed, on the basis of FIG. 4A through FIG. 9B.

In FIG. 4A AND FIG. 4B are first action views illustrating steps in themanufacture of a fuel cell separator according to the invention.

In FIG. 4A, along the edge 22 c of the central part 22, which is a metalmember, a primer treatment is carried out on the upper and lower faces22 a, 22 b. That is, silicone rubber is baked onto the upper and lowerfaces 22 a, 22 b at a temperature of 150° C. to form primer-treatedparts 25 a, 25 b.

In FIG. 4B, the central part 22 with the primer-treated parts 25 a, 25 bis placed on a fixed die 51 on a turntable 50 as shown by the arrow [1].Then, by the turntable 50 being turned as shown by the arrow [2], thefixed die 51 is brought to rest under a first movable die 52.

The fixed die 51 and the first movable die 52 form a peripheral partmold for injection-molding the peripheral part 30 of the separator 20shown in FIG. 1 and FIG. 2.

FIG. 5A and FIG. 5B are second action views showing a process formanufacturing a fuel cell separator according to the invention.

In FIG. 5A, by the first movable die 52 being lowered as shown by thearrows [3], the peripheral part mold is closed.

In FIG. 5B, by a plunger 56 of a peripheral part injecting device 55shown in FIG. 4B being operated, a molten resin 57 of an engineeringplastic is injected into a peripheral part cavity 58 as shown by thearrows [4].

FIG. 6A and FIG. 6B are third action views showing a process formanufacturing a fuel cell separator according to the invention, FIG. 6Abeing an enlarged view of the part 6B in FIG. 5B.

In FIG. 6A, with multiple projections 51 a of the fixed die 51projecting toward the first movable die 52 inside the peripheral partcavity 58 and multiple shoulder parts 51 b protruding inside theperipheral part cavity 58, the peripheral part cavity 58 is filled withthe molten resin 57.

As a result, when the peripheral part 30 is molded, hydrogen gaspassages 31, oxygen gas passages 32 and product water passages 33 (theflow passages 32, 33 are shown in FIG. 1) are formed, and passagerecesses 35 are molded at the edges of these flow passages 31, 32, 33.

Also, a core 59 is made to project slightly into the peripheral partcavity 58 from the fixed die 51, projections 52 a of the first movabledie 52 are made to project as far as the core 59, and shoulder parts 52b are made to project slightly into the peripheral part cavity 58,whereby a thin part 37 is formed and second openings 38 are formed inthe thin part 37.

Then, after the molten resin 57 has set inside the peripheral partcavity 58, the core 59 is withdrawn from inside the peripheral partcavity 58 as shown by the arrow [5].

In FIG. 6B, by the first movable die 52 being raised as shown by thearrows [6], the peripheral part mold is opened. This ends the step ofinjection-molding the peripheral part 30.

FIG. 7A and FIG. 7B are fourth action views showing a process formanufacturing a fuel cell separator according to the invention.

In FIG. 7A, by the turntable 50 being turned as shown by the arrow [7],the fixed die 51 is brought to rest under a second movable die 61.

The fixed die 51 and the second movable die 61 form an elastic membermold for injection-molding the elastic member 40 of the separator 20shown in FIG. 1 and FIG. 2.

In FIG. 7B, by the second movable die 61 being lowered as shown by thearrows [8], the elastic member mold is closed.

FIG. 8A and FIG. 8B are fifth action views showing a process formanufacturing a fuel cell separator according to the invention.

In FIG. 8A, by the elastic member mold being closed, an elastic membercavity 67 is formed by the fixed die 51 and the second movable die 61,and seal cavities 68 are formed by the second movable die 61 and theperipheral part 30.

In this state, by a plunger 65 of an elastic member injecting device 64shown in FIG. 7A being operated, a molten resin 66 of silicone rubber isfilled into the elastic member cavity 67 and the seal cavities 68 asshown by the arrows [9].

In FIG. 8B, by the elastic member cavity 67 being filled with the moltenresin 66, the upper and lower primer-treated parts 25 a, 25 b of thecentral part 22 are covered with an elastic member 40, the thin part 37of the peripheral part 30 is covered with the elastic member 40, and acentral seal part 41 is molded.

Here, although the central part 22 is a metal member, because theprimer-treated parts 25 a, 25 b have been provided at the periphery ofthe central part 22, the elastic member 40 can be adhered well to thecentral part 22.

In addition, by the first openings 26 and the second openings 38 beingfilled with the elastic member 40, first anchors 42 and second anchors43 can be formed in the first openings 26 and the second openings 38respectively.

By this means, the central part 22 can be prevented from detaching fromthe elastic member 40, and the peripheral part 30 can be prevented fromdetaching from the elastic member 40.

And, at the same time as the elastic member cavity 67 is filled with themolten resin 66, by the seal cavities 68 formed by the second movabledie 61 and the peripheral part 30 being filled with the molten resin 66,passage seal parts 34 are formed.

By this means, in the molding of the elastic member 40, the passage sealparts 34 and the central seal part 41 can be molded from silicone rubber(rubber material) simultaneously. Thus, the elastic member 40, thepassage seal parts 34 and the central seal part 41 can be formed easilyin a short time.

FIG. 9A and FIG. 9B are sixth action views showing a process formanufacturing a fuel cell separator according to the invention.

In FIG. 9A, after the molten resin 66 in the elastic member cavity 67and the molten resin 66 in the seal cavities 68 has been allowed to set,the elastic member mold is opened by the second movable die 61 beingraised as shown with arrows.

By this means, the step of injection-molding the elastic member 40 andthe passage seal parts 34 is completed, and a fuel cell separator 20 canbe obtained.

In FIG. 9B, after the elastic member mold is opened, by the turntable 50being turned as shown with an arrow, the fixed die 51 is brought to restat a loading/unloading area 69. Next, the fuel cell separator 20 isremoved from the fixed die 51 as shown with an arrow. By this means, theprocess of manufacturing a fuel cell separator 20 is completed.

As explained with reference to FIG. 4A through FIG. 9B, as a result ofbeing so constructed that a peripheral part 30 of the separator 20 isconnected to a central part 22 by an elastic member 40, the separator 20can be manufactured relatively easily. Therefore, the yield in themanufacture of separators 20 can be raised, and the productivity ofseparators 20 can be increased.

Although silicone rubber is exemplified as the elastic member 40 and thepassage seal parts 34 in the above embodiment, the elastic member 40 andthe passage seal parts 34 are not limited to it and another rubber andresins may be used therefore.

Although in the embodiment described above an example was describedwherein stainless steel was used for the metal member forming thecentral part 22 of the fuel cell separator 20, the metal member formingthe central part 22 is not restricted to this.

Also, although in the embodiment described above an example wasdescribed wherein an engineering plastic was used for the resin memberforming the peripheral part 30 of the fuel cell separator 20, the resinmember forming the peripheral part 30 is not restricted to this.

And although in the embodiment described above an example was describedwherein a projecting central seal part 41 surrounding the central part22 of the separator 20 was provided on the elastic member 40, there isno restriction to this, and alternatively the projecting central sealpart 41 surrounding the central part 22 may be not provided on theelastic member 40.

Also, although in the embodiment described above an example wasdescribed wherein projecting passage seal parts 34 surrounding the gaspassages 31 and 32 and the product water passages 33 were provided onthe peripheral part 30 of the separator 20, the passage seal parts 34may alternatively be not provided.

And whereas in the embodiment described above an example was describedwherein the elastic member 40, the central seal part 41 and the passageseal parts 34 were formed integrally from a rubber material, there is norestriction to this, and the elastic member 40, the central seal part 41and the passage seal parts 34 can also each be formed individually, andthe respective members 40, 41, 34 can also be each formed from adifferent material.

Also, whereas in the embodiment described above hydrogen gas and oxygengas were used as examples of reaction gases and product water was usedas an example of a reaction product, there is no restriction to this,and the invention can also be applied to other reaction gases andreaction products.

INDUSTRIAL APPLICABILITY

By making the whole of the peripheral part of a separator a resin memberand forming gas passages and product water passages in this peripheralpart, it is possible to ensure resistance of the gas passages andproduct water passages to corrosion by reaction gases and product water.Because of this the fuel cell has excellent corrosion resistance and isparticularly useful as a fuel cell for use in an automotive vehicle.

1. In a fuel cell separator having a central part and a peripheral part,said peripheral part defining a reaction gas passage for guidingreaction gases and a reaction product passage for guiding a reactionproduct, reaction gases being guided from the reaction gas passages tothe central part and reaction product produced at the central part beingguided to the reaction product passage, wherein the central part is madefrom a metal member and the peripheral part is made from a resin memberand said resin member being connected to the metal member by an elasticmember.
 2. The fuel cell separator according to claim 1, wherein aprojecting central seal part surrounding the central part is provided bythe elastic member.
 3. The fuel cell separator according to claim 1,wherein the peripheral part includes projecting passage seal parts thatsurround the reaction gas passages and the reaction product passage. 4.The fuel cell separator according to claim 2, wherein the elastic memberand the central seal part are formed integrally from a rubber material.5. The fuel cell separator according to claim 2, wherein the peripheralpart includes projecting passage seal parts that surround the reactiongas passages and the reaction product passage.